val initial_knowledge = [
{p="",c="Thing",a=[]}
,{p="Thing",c="Plant",a=[]}
,{p="Plant",c="Tree",a=[]}
,{p="Thing",c="Animal",a=[]}
,{p="Animal",c="Mammal",a=[]}
,{p="Mammal",c="Human",a=[]}
,{p="Human",c="Nicholas",a=[]}
,{p="Human",c="Sebastian",a=[]}
,{p="Human",c="Anthony",a=[]}
,{p="Thing",c="Robot",a=[]}
,{p="Robot",c="NAO",a=[]}
]